4 Reasons Why One Of The Air Handlers In Your Ductless AC Isn't Working Correctly

About Me
How to Keep Your Cool When the Mercury is Rising

When the heat is rising to record-breaking levels, it can be really tough to stay cool. This summer, I found that my air conditioner had trouble keeping up with the temperatures. It wasn't that the AC wasn't working, it was just that I couldn't seem to get my house cooled down as much as I wanted. I worried that I would have to replace the whole AC system. Luckily, I have a good friend who works as an HVAC contractor. He took a look at my system and gave good news -- it didn't need to be replaced. Instead, he shared a lot of tips for helping my air conditioner work more efficiently, as well as some ideas to help supplement the AC and keep the house cooler. I'm using those tips to create this blog to share ways for all of us to keep cool on the hottest days.

4 Reasons Why One Of The Air Handlers In Your Ductless AC Isn't Working Correctly

28 September 2022
 Categories: , Blog


The indoor air handlers of a multi-zone split air conditioner work independently to provide indoor cooling. Each air handler has a temperature sensor and thermostat controls that allow users to set the desired temperatures in each zone. Therefore, if one of your zones isn't cooling correctly, some components of the indoor unit are faulty. Below are four potential reasons why your air handler isn't working correctly.

Faulty Temperature Sensor

Each air handler in a multi-split system has an ambient temperature sensor. This device reads and compares the ambient temperature against the thermostat setting. If the temperature is high, it signals the AC to turn on and cool the zone to the pre-set temperature. Therefore, a faulty sensor may fail to detect ambient temperature. Consequently, it fails to signal the air conditioner to start a cooling cycle. Repair the faulty sensor to restore cooling in the affected zone.

Damaged Evaporator Coil

The evaporator coils extract heat from the indoor air and lower the temperature. Defects in the evaporator can cause your air handler to stop working efficiently. For example, if the coils are dirty, the dirt will prevent them from absorbing all the heat from the space. As a result, your AC will blow warm air back into the room.

Similarly, if the coils are cracked, the refrigerant may leak out of the system. With low refrigerant, there won't be adequate fluid to absorb heat from the indoor space. Therefore, your AC will blow warm air into the home. Refrigerant leaks may affect the performance of the other air handlers in your house as well. Therefore, replace the damaged coils and recharge your air conditioner.

Dirty or Clogged Air Filter

Each air handler has an air filter that traps pollutants in the indoor air. Over time, the filters become clogged or dirty due to the buildup of dirt and debris. Clogged filters impede airflow and prevent the zone from cooling down as fast as it should. The blockage can also cause the air handler to overheat and shut down. Therefore, clean clogged air filters and replace worn ones to improve airflow in the zones.

Faulty Blower Fan

The blower fan is the component that blows conditioned air into the room. If the fan's motor is defective, the fan's blades will fail to rotate or do so at a slow speed. As a result, the room will take a long time to cool down. If the fan fails to rotate, the air handler will run, but there won't be any cooling. You must replace the defective motor to restore the fan's operation.

Troubleshoot your air handler for the above issues and repair it to restore efficient cooling. Contact an air conditioning company such as Mid Atlantic Mechanical and Repair, LLC for professional repair services.